1. Field of the Invention
The present invention relates generally to automotive switches and, in particular, to an illumination device for illuminating the knob of a switch, such as a hazard switch or a rear-defogger switch of an automobile.
2. Description of the Prior Art
A conventional illumination device for illuminating the knob of switches is disclosed, for example, in Japanese Utility Model Publication Laid-Open No. 4-72519. The conventional illumination device includes an illuminating section which is mounted on a knob, and a light source which is mounted at the back surface of the knob. In the conventional illumination device, the luminance of the illuminating section was sometimes insufficient, because the light source is surrounded by rubber material or a resin member with black color, thereby utilizing only directly emitted light beams for the purpose of illuminating the knob, although a transparent material is used for the illuminating section.
Another conventional illumination device is disclosed in Japanese Utility Model Publication Laid-Open No. 6-62438. In this conventional illumination device, a light source is disposed at the back side of a push switch, and there is mounted a hollow-shaped reflector surrounding the light source fixed on the knob, in order to provide a sufficient luminance.
According to the above-mentioned conventional devices, even though sufficient luminance may be obtained by providing such reflectors, the devices undesirably require more expense and result in poor productivity because of the necessity of providing such reflectors.